1. Field of the Invention
The present invention relates to a sanitary napkin with a projection on a body surface of a main body, and more particularly to a sanitary napkin whose projection can easily conform to the contour of the wearer's crotch, ensuring contact with the wearer's body so as to be effective in preventing leakage of menstrual blood.
2. Description of the Related Art
There have been known sanitary napkins of the type including a main body with a liquid-absorbent layer and a projection disposed on the body surface of the main body.
Japanese Unexamined Patent Application Publication No. H11-33054 discloses a sanitary napkin including a liquid-absorbent layer and a topsheet covering the body surface of the liquid-absorbent layer. The body surface of the sanitary napkin is formed with a groove where the topsheet and the liquid-absorbent layer are pressed together. The groove defines a longitudinally elongated enclosure. The enclosure bulges beyond the surround surface.
Japanese Unexamined Patent Application Publication No. 2000-83993 discloses a sanitary napkin whose liquid-absorbent layer is composed of separate upper and lower cores. The lower core is integral with a liquid-impermeable lower sheet. On the body surface side of the lower core, there is provided a liquid-permeable upper sheet. Front and rear ends of the upper sheet are secured to the lower core, and elastic members are secured to the upper sheet in order to exert a longitudinal elastic contractive force. The upper core is also secured to the upper sheet. The upper core, as well as the upper sheet, can be raised from the lower core by the elastic contractive force. The upper core can face the wearer's vulva while the outer surface of the lower sheet is attached to the inner surface of a crotch portion of an undergarment. Since the upper core is movable independently of the lower core, the upper core can easily be kept in contact with the vulva to absorb menstrual blood, thereby preventing leakage of menstrual blood out of the napkin.
In the sanitary napkin disclose in JP H11-33054, as set forth above, the enclosure defined by the groove is relatively thick and elongated longitudinally of the sanitary napkin. Since the surface deformation properties and compression properties under body pressure are almost uniform within the enclosure, the enclosure cannot readily conform to the contour of the wearer's crotch, i.e., follow the irregularities due to the vaginal opening surrounded by the labia majora, the posterior commissure of labia majora, the perineum, the anus, and the intergluteal cleft. In addition, since the thickness of the enclosure is maintained only by the liquid-absorbent layer, when the liquid-absorbent layer is wetted and compressed by the body pressure, the enclosure will be inferior in compression recovery, creating a clearance between the wearer's crotch and the sanitary napkin.
In the sanitary napkin disclose in JP 2000-83993, on the other hand, the upper core can easily be kept in contact with the vaginal opening. In front of and behind the upper core, however, nothing is provided between the upper sheet and the lower core. Therefore, when the upper core is pushed down into contact with the lower core by the body pressure, it is difficult to keep the upper sheet in contact with the wearer's body in front of and behind the upper core. Particularly, it is difficult to keep the upper sheet in contact with the perineum and the anus.
If the sanitary napkin is not kept in contact with the perineum and the anus, for example, menstrual blood cannot be prevented from migrating rearwardly from the vaginal opening in a sleeping or chair-sitting position, thereby causing rearward leakage of menstrual blood.